In bowl of stand mixer cream butter and sugar together until light and fluffy. Add egg and vanilla and continue mixing until smooth.

Add flour mixture and milk in alternating amounts, starting and ending with flour. Stir until just blended.

Pour in springform pan. Bake for 25 minutes until center is set and toothpick comes out clean.

Cheesecake Layer

Lower oven temperature to 325*

In bowl of stand mixer beat cream cheese, sugar and vanilla together on medium-high speed until smooth.

Separately whisk eggs with a fork in a small bowl, add beaten eggs to cream cheese mixture on low until just combined. Stir in sour cream. Pour mixture over cake in the spring form pan, spreading to cover.

Bake for 45-50 minutes until the outside edges appear set when gently shaken. Cool in pan on a wire rack for 15 minutes.

Loosen the edges of cake from the pan by running a butter knife around the cake.Allow cake to cool completely. Cover cake and chill for at least 4 hours or over night

Chocolate layer

When cheesecake is chilled heat heavy cream in a small saucepan until it almost comes to a boil. Remove from heat and stir in chocolate chips until melted. Stir in butter until smooth.